//泛型
class Message<T>{
    private T message;

    public T getMessage(){
        return message;
    }

    public void setMessage(T message){
        this.message = message;
    }
}

public class TestDemo4 {

    public static void main(String[] args) {
        Message<Integer> message = new Message<>();
        message.setMessage(1);
        fun(message);
    }
    //通配符？
    public static void fun(Message<?> temp){
        System.out.println(temp.getMessage());
    }
}
